Fix Env vars

There was a bug in vars_os() where the vriable name contained NULL on
the Rust side. It is fixed now

Signed-off-by: Ayush <ayushsingh1325@gmail.com>

Author: Ayush1325

library/std/src/sys/uefi/os.rs

@@ -110,7 +110,7 @@ impl Iterator for Env {
         self.last_var_name = k;
         match val {
             None => self.next(),
-            Some(x) => Some((OsString::from_ucs2_lossy(&key), x)),
+            Some(x) => Some((OsString::from_ucs2_null_termintated(&key), x)),
         }
     }
 }
@@ -271,12 +271,17 @@ pub(crate) mod uefi_vars {
         last_var_name: &[u16],
         last_guid: &r_efi::efi::Guid,
     ) -> io::Result<(Vec<u16>, r_efi::efi::Guid)> {
+        #[inline]
+        fn buf_size(s: usize) -> usize {
+            s / size_of::<u16>()
+        }
+
         let mut var_name = Vec::from(last_var_name);
         let mut var_size = var_name.capacity() * size_of::<u16>();
         let mut guid: r_efi::efi::Guid = *last_guid;
         match unsafe { get_next_variable_raw(&mut var_size, var_name.as_mut_ptr(), &mut guid) } {
             Ok(_) => {
-                unsafe { var_name.set_len(var_size / size_of::<u16>()) };
+                unsafe { var_name.set_len(buf_size(var_size)) };
                 return Ok((var_name, guid));
             }
             Err(e) => {
@@ -286,12 +291,11 @@ pub(crate) mod uefi_vars {
             }
         }
 
-        var_name.reserve(var_size - (var_name.capacity() * size_of::<u16>()));
+        var_name.reserve(buf_size(var_size) - var_name.capacity() + 1);
         var_size = var_name.capacity() * size_of::<u16>();
 
         unsafe { get_next_variable_raw(&mut var_size, var_name.as_mut_ptr(), &mut guid) }?;
-
-        unsafe { var_name.set_len(var_size / size_of::<u16>()) };
+        unsafe { var_name.set_len(buf_size(var_size)) };
         Ok((var_name, guid))
     }
 

src/test/ui/process/try-wait.rs

@@ -3,7 +3,7 @@
 #![allow(stable_features)]
 // ignore-emscripten no processes
 // ignore-sgx no processes
-
+// ignore-uefi spawn function is blocking. Also kill not implemented.
 #![feature(process_try_wait)]
 
 use std::env;
@@ -18,13 +18,10 @@ fn main() {
             "sleep" => thread::sleep(Duration::new(1_000, 0)),
             _ => {}
         }
-        return
+        return;
     }
 
-    let mut me = Command::new(env::current_exe().unwrap())
-                         .arg("sleep")
-                         .spawn()
-                         .unwrap();
+    let mut me = Command::new(env::current_exe().unwrap()).arg("sleep").spawn().unwrap();
     let maybe_status = me.try_wait().unwrap();
     assert!(maybe_status.is_none());
     let maybe_status = me.try_wait().unwrap();
@@ -38,15 +35,12 @@ fn main() {
     let status = me.try_wait().unwrap().unwrap();
     assert!(!status.success());
 
-    let mut me = Command::new(env::current_exe().unwrap())
-                         .arg("return-quickly")
-                         .spawn()
-                         .unwrap();
+    let mut me = Command::new(env::current_exe().unwrap()).arg("return-quickly").spawn().unwrap();
     loop {
         match me.try_wait() {
             Ok(Some(res)) => {
                 assert!(res.success());
-                break
+                break;
             }
             Ok(None) => {
                 thread::sleep(Duration::from_millis(1));